Oracle 18c

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CREATE TABLE mytable
    (userid varchar2(30), term_code int, race varchar2(3), gender varchar2(3))
;
INSERT ALL 
    INTO mytable (userid, term_code)
         VALUES ('Bob', 201810)
    INTO mytable (userid, term_code)
         VALUES ('Bob', 201910)
    INTO mytable (userid, term_code)
         VALUES ('Bob', 201930)
    INTO mytable (userid, term_code)
         VALUES ('Bob', 201940)
    INTO mytable (userid, term_code)
         VALUES ('Bob', 202010)
    INTO mytable (userid, term_code)
         VALUES ('Tim', 201820)
    INTO mytable (userid, term_code)
         VALUES ('Tim', 201940)
    INTO mytable (userid, term_code)
         VALUES ('Tim', 202010)
    INTO mytable (userid, term_code)
         VALUES ('Fred', 201810)
    INTO mytable (userid, term_code)
         VALUES ('Fred', 201910)         
SELECT * FROM dual
;
10 rows affected

select m.* from mytable m
where m.term_code = (
  case when not exists (select 1 from mytable where userid = m.userid and term_code = 201930) 
    then 201940
    else 201930
  end
)


USERID
TERM_CODE
RACE
GENDER


Bob
201930
null
null

Tim
201940
null
null


select userid, min(term_code) term_code
from mytable 
where term_code in (201930, 201940)
group by userid


USERID
TERM_CODE


Bob
201930

Tim
201940


select m.*
from mytable m inner join (
  select userid, min(term_code) term_code
  from mytable 
  where term_code in (201930, 201940)
  group by userid
) t on t.userid = m.userid and t.term_code = m.term_code


USERID
TERM_CODE
RACE
GENDER


Bob
201930
null
null

Tim
201940
null
null


select t.userid, t.term_code, t.race, t.gender
from (
  select m.*,
    row_number() over (partition by userid order by term_code) rn  
  from mytable m
  where m.term_code in (201930, 201940)
) t 
where t.rn = 1


USERID
TERM_CODE
RACE
GENDER


Bob
201930
null
null

Tim
201940
null
null